Two major groups were identified by principal component, phylogenetic, and identity by descent (IBD) analysis: Middle Eastern Jews and European/Syrian Jews.

An apparent North African ancestry component was also observed as was present in the Sephardic groups potentially reflecting gene flow from Moorish to Jewish populations in Spain from 711 to 1492. Yet the admixture with European people explains why so many European and Syrian Jews have blue eyes and blonde hair.'" Razib Khan.

'Previous genetic studies of blood group and serum markers suggested that Jewish groups had Middle Eastern origin with greater genetic similarity between paired Jewish populations,' says senior study author, Dr. 'More recent studies of Y chromosomal and mitochondrial DNA have pointed to founder effects of both Middle Eastern and local origin, yet, the issue of how to characterize Jewish people as mere coreligionists or as genetic isolates that may be closely or loosely related remained unresolved. Yet the genomes of the Jewish Diaspora groups have distinctive features that are representative of each group's genetic history.' says Dr. 'Our study demonstrated that the studied Jewish populations represent a series of geographical isolates or clusters with genetic threads that weave them together,' added Dr. The researchers identified distinct Jewish population clusters that each exhibited a shared Middle Eastern ancestry, proximity to contemporary Middle Eastern populations and variable degrees of European and North African genetic intermingling. The two major groups, Middle Eastern Jews and European Jews, were timed to have diverged from each other approximately 2500 years ago.

Southern European populations show the greatest proximity to Ashkenazi, Sephardic and Italian Jews, reflecting the large-scale southern European conversion and admixture known to have occurred over 2,000 years ago during the formation of the European Jewry. Ostrer noted, 'The study supports the idea of a Jewish people linked by a shared genetic history.

Order a DNA kit from FTDNA's headquarters in the USA This page collects Y-DNA and mt DNA data and analysis related to traditionally Rabbinical Jewish populations of the world, including: Ashkenazim (Jews of Northern and Eastern Europe) • Sephardim (Spanish and Portuguese Jews) • Mizrakhim (Middle Eastern Jews) • Italkim (Italian Jews) • Caucasian Mountain Jews (Dagestani and Azerbaijani Jews) • Georgian Jews • Indian Jews • North African Jews • Yemenite Jews • Ethiopian Jews Steven M. However, paradoxically we also found higher genetic diversity, a sign of an older or more admixed population but not of a long-term isolate.

Also used for comparison were 3 Middle Eastern populations: Palestinian Arabs, Druze, and Bedouins.

However, these and successor studies of monoallelic Y chromosomal and mitochondrial genetic markers did not resolve the issues of within and between-group Jewish genetic identity.

The researchers were able to estimate that between 35 and 55 percent of the modern Ashkenazi genome comes from European descent.

[...] He adds that his group's analysis agrees with a recently published study from New York University and Albert Einstein College of Medicine, and supports estimates of a high level of European admixture, accounting for up to half of the genetic make-up of contemporary Ashkenazi.

"Signatures of founder effects, admixture, and selection in the Ashkenazi Jewish population." Proceedings of the National Academy of Sciences of the United States of America (PNAS) 1 (September 14, 2010): pages 16222-16227. Among the comparative populations were 1705 continental Europeans and 1251 European-Americans.